An Oath To Kill
by KissingFire
Summary: Mid CoB. Alec swore by an oath he'd kill Clary if she told Jace his darkest secret. So when she does, what else can he do but stand by his oath? M for violence and language.


**AN: The first time I read City of Bones, and Alec swore to kill Clary if she told Jace he was in love with him, I wondered what he would do if she _did _tell. **

**And this is what I finally came up with, three years later. :)**

**Universe: Shadowhunters. OOC.**

**Warning(s): No spoilers. Torture scene.**

**Rated M for: Violence/Language/Torture. If you love Alec, you may not like this. If you like Clary, you may not like this. I write what I write. :)**

**Disclaimer: Cassie owns the characters. I just make 'em into psychotic killers. ;)**

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><p><em>Alec<em>

...

...

He couldn't believe he'd actually sworn _the_ oath. He'd never used it, ever. Then again, he'd never panicked like that, or acually hated somebody with a burning passion like he did with that stupid, moronic _mundie _girl.

And Jace liked her. Like, _liked _her.

Alec felt his face twist into a furious sneer as he sharply pulled the arrow back, aiming for the dummie's neck. He wasn't a violent person. Never killed a demon in his life. He was content with protecting Izzy and Jace, he didn't need the rush or glory of killing one of the assholes that blended in at mundane clubs or restraunts.

He let the arrow fly; Piercing right through the throat.

_If only it was Clary's throat._

The welcome image clouded his mind: Clary, tied up and hanging a foot above the ground, gag in her fat, buck-toothed mouth. Her green eyes, which stuck out like bug eyes, wide and terrified. _Terrified of **him**. _

Alec smiled grimly. Ah, yes. She should be afraid. He would walk around her, surveying how her delicate, bird-like bones stuck out through her skin like a skeletons, looking for where he was sure it would hurt her the most. Then he'd strike at her. Over and over, bruising her too-pale skin, staining her clothes with blood that he wanted so badly to draw.

His grip on the bow tightened until it snapped in half. Like he'd snap the little bitch's neck.

Alec smirked, turning to walk out of the Training Room, spotting his reflection in the giant mirror that covered the wall. He'd normally immediately look away, ashamed to see someone so weak, so worthless. So _revolting. _People like him weren't accepted in the Council, it was so much worse than the way mundies treated them.

But now, he saw a hunter, rather than the victim. The predator, rather than the prey. He was the killer now. His reflection's mouth lifted into a feral, dangerous grin.

_Now all he had to do was wait._

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><p>"Uh, Jace?" Her annoyingly high-pitched squeak reached his ears through the door to his foster brother's bedroom.<p>

Alec tapped his fingers against the marble floors, waiting for what she was going to say next. She was so disgustingly predictable. Pathetically weak. Like a baby who needed to be fed, carried around, clothed and bathed.

"Yeah?" Alec closed his eyes at Jace's warm, husky voice. _I could listen to that voice forever._

"I don't know how to say this..." _Yes, yes, yes! _Alec's finger-tapping became faster, harder. _Say it. Rat me out. The faster you do, the faster I can kill your pathetic, whiny ass._

"I think Alec's gay."

And there it was: The burning fire in his veins, his fingers twitching and his brain beginning to click in killer-mode. _This is what it feels like to swear an Oath._

Alec felt his face split into a wide smile; To anyone else, it would've looked off, maniacal even. But he was just _so_ happy_. Kid, you just made this so much easier for me._

"Gay?" He heard Jace's mattress squeak. "What makes you think that?"

"He-Jace, Alec has a crush on you."

Silence.

Then Jace chuckled, a warm, soft sound. "Can you blame him?"

Clary giggled. "I guess not."

_Whore. Skank. When you come out here, I swear to the Angel I'll cut your tongue off._

Jace sighed. "I'll talk to him. I never realized..."

"No!" Alec snickered under his breath at the raw panic in her voice. "Don't-don't tell him. He doesn't know I'm telling you, and I'd rather he didn't-"

"Little Girl, relax," Jace soothed. "I won't."

_Since when has he become Mr. Empathy? _

Clary took a shuddering breath. "Thank you..."

He heard a pair of feet land on the floor, and the bedsprings groaned. _Come to me..._

"I'm gonna go get something to drink," he heard her say to Jace. "I'll be right back."

_No, you won't._

Alec stood up, leaning against the wall with his arms crossed. Waiting.

The door opened, and Clary turned to shut it, and jumped when she saw him standing there. "Alec! What-what're you doing here?"

He forced himself to smile gently at her; He didn't want to scare her. Yet. He didn't need her alerting Jace that there was something wrong. Because he couldn't bring himself to hurt Jace, Oath or not.

"I was just looking for you." She instantly relaxed; Stupid girl.

"Oh. Alright. What did you want?"

He smirked inwardly. _I want you to pay. I want you to feel that same pain I felt every time I saw him staring at you, touching you..._

"I wanted to show you something." At her suspicious look, he chuckled and raised his hands. "Relax, it's just this weapon I thought you'd find handy, in case you wanted to start your training as one of _us," _he spat "us" because she'd never be one of them. She'd never be a true Nephilim.

Clary's face brightened. "Cool."

Alec wanted to laugh. It was almost too easy. "C'mon." He began walking towards the basement, where none of them ever went, except to store old furniture, paintings and weapons that nobody ever used. He had to restrain himself from running, that's how eager he was.

Of course, because she was so short and her legs were thin like a chicken's, he had to walk extra slow for her to catch up.

He walked down the stairs, because the elevator didn't go that far underground. "Alec?" He turned around to stare at her; But it was dark, since there were no lights in the staircase, so he couldn't see her expression. Except the wobble in her voice was enough to let him know she was nervous. _Good. Maybe she wasn't as big of an idiot as he'd thought._

"Are you sure this is the right way?"

"I've lived here for seventeen years, Clary." _Don't lose your temper with her. You want to get her in the basement, where she can't run, and where no one will hear her scream for help. Stay calm. _"I'm pretty sure I know my way around here."

"Alright." She didn't sound sure, but what she felt meant little to him.

Thankfully, she remained silent for the remainder of the walk down. Angel. Good thing too, because if he heard her dolphin-like voice one more time, he might just skip right to the murder part and push her down the stairs.

"We're here," Alec announced, pushing open the wooden door.

Clary stuck her head in. "Uh, Alec? I can't see in here."

He rolled his eyes, and gently pushed her in. "You will." Closing the door soundly behind him, and sliding the deadbolt in, he pulled his _stele _out of his pocket and slashed the restraint rune onto the oak.

"Alec?" Her voice definitely sounded scared, now. "What's going on? Why'd you lock the door?"

He allowed himself to smile. Diggin in the pocket of his worn jeans, he pulled out his witchlight, illuminating the dungeon-like room, his and Clary's shadows dancing along the steel walls.

Clary sucked in her breath, looking around the room. "It's so..." She stopped, and turned to look at him. "Alec. We aren't in here for a weapon, are we?"

He kept his serene smile plastered across his face, and shook his head at her.

She gulped. "Why did you bring me down here, then?"

Alec clapped his hands together, and slowly, with no rush, began circling around her, eyeing her like a buzzard might eye a dead animal. Which was what she was, practically. A dead animal.

"I think you know why, dear Clary," he hummed cheerfully.

Her face paled, making her drastic freckles stand out even more, and her bug-eyes seemed disgustingly larger. "I-I don't know what you're talking about," she lied.

Alec chuckled; Moronic child. As if she could lie to him.

Then, quick as a snake, he had her by the throat, raising her in the air so that she was above his head.

Her hideous face turned a delightful shade of purple, and she made a strangled choking sound, her nails clawing at the tight grip he had around her neck.

"Lets try that again, shall we?" He asked, his voice dangerously soft as he squeezed even tighter, and took a great pleasure as her eyes bugged out. Like a chew toy.

He abruptly dropped her, and she fell in a heap at his feet. Pathetic mundie.

She began coughing violently, struggling to gain her breath back. But Alec was not feeling very patient, right then. Raising back his sneakered-foot, her kicked her sharply in the ribs, and grinned widely when he heard a cracking sound.

Clary yelped, and looked up at him, her terror-filled eyes shining. "Why are you doing this?" She whispered. "Why are you hurting me?"

Anger flooded through him, along with images of her and Jace: The way Jace had stared at her, at Pandemonium. The way Jace wouldn't shut the hell up about her as they left Pandemonium, saying how fascinatingly odd it was that the mundie girl could see them. The way Jace would brush his fingers against her shoulder, arm, and hair without thinking about it. How his eyes softened when he spoke to or about her.

He brought his fist down, hitting her square in the mouth and causing her to fall back to the floor, blood filling her mouth.

Alec sneered down at her. "Wrong answer."

"I'm sorry!" She gave a small sob, blood spitting out of her mouth as she did so. "I'm sorry, alright? I shouldn't have told him that you were in love with him, that was wrong-"

Alec gave a curse, and her mouth snapped shut. He knelt down in front of her, and the closer he got, the more she began trembling, crawling back and away from him.

"Shh," he crooned, slowly reaching his hand out towards her. She let out a whimper as his fingers gently trailed down her bruising cheek. _Beautiful. _Nothing more beautiful than a large bruise to cover up an ugly face.

"Clary, it's alright," he murmured. "Don't be afraid."

She dropped her hand from where she'd had it covering her mouth. "What are you going to do to me?" She asked in a shaky whisper, a tear tracking down her cheek.

Alec tilted his head to the side, and grinned at her, making her shudder. "I am," he hummed, running a single finger up to her eyebrow, digging his nail into her skin and dragging down, causing a shallow cut to open, a small trickle of blood ran down Clary's face, like a scarlet tear, "going to do exactly what I swore I would do."

Her eyes squeezed shut and her breathing cut sharply. "Oh." Her voice was small.

Alec stood up, grabbing her by the end of one of her stupid pigtails and yanking her across the room.

Clary clutched at her scalp, but he didn't relent until he reached the silver manacles that hung from the ceiling. His parents had them for werewolves, but ever since the Accords, they weren't allowed to use them. Legally, anyhow. Jace used them once. With a fae girl who had...Adventurous taste in the bedroom apparently, and got off on being tied up and whipped.

"Alec, please," she pleaded when she realized what he was doing. "Don't-" His hand whipped across her face with enough force to send her head snapping to the left. "Shut _up," _he snarled at her, feeling his hands shake with anger. "Angel. Just stop talking. Or I swear by the Angel, I will cut your tongue and feed it to the damn cat."

She shut up.

Satisfied, Alec grabbed her by both wrists, and snapped them to each manacle, suspending her at least two feet in the air.

Frantically, Clary swung her legs back and forth attempting to kick Alec.

He rolled his eyes, and reached forward, grabbing each foot. Fear crossed her face.

"Now, now," he tsked. "Trying to kick me, Clarissa? That's not very nice." He smiled sweetly at her. "I can't have that, now." He ran his hands up, wrapping them around each bony ankle. Then he jerked them both in the opposite direction sharply, and Clary threw her head back and let out a shrill, piercing scream, breaking off with a sob.

He giggled at the sound of her think bones snapping, and dropped her now-broken-ankles, where they hung limply and uselessly beneath her.

Clary was silently crying, and was biting into one of the chains, trying to keep from making too much noise.

Alec shook his head. "Clary, Clary." He patted her on one of her ankles, and she gave a twitch of pain. "Don't you know? I don't want to hurt you...But I just can't fight the Oath." _Even if you hadn't told him, I would've killed you. For all the times you've almost gotten him killed._

"I'm sorry," she sobbed. "Please, let me go. I'm sorry-"

"Sorry doesn't mean anything, Clary."

_Sorry won't make Jace fall in love with me._

Alec sighed. "Now. If you could refrain yourself from attempting to attack me, I would like to get this over with. The very sight of you is making me nauseas."

He turned and walked over to the table of unused weapons. Knife? Hmm...It'd be handy. Izzy's old whip from when she was eleven? Definitely. The taser Jace swiped from that officer that tried to arrest him when he caught him with a dagger? He did want to make her scream...

Alec nodded, satisfied with his little kit.

He walked back over to Clary, who was eyeing him dreadfully.

Alec pulled the whip out, first. She took one look at it, and sucked in a breath. "Oh, Jesus..."

"He isn't here right now," Alec said cheerfully, unwinding the silverish coil from the little ball it's been rolled into. Robert had gotten her the golden whip for her fifteenth birthday because at the time, yellow was her favorite color-She'd also been going through a "Jace" phase-and she'd gotten too tall for this one. And had tossed this one down in the basement, forgotten.

"Clary...Tell me. How do you feel about Jace?"

She opened her eyes, and stared down at him. "Jace? H-he's alright."

_Fucking liar. _

Alec brought the whip down across her stomach sharply, and she arched forward with a shriek, her hands clenching into fists around the manacles covering her wrists.

"The truth, if you would," he demanded in a cool, harsh voice. "I am not in the mood for lies, Clarissa." He snapped the whip threateningly.

"Okay, okay!" She took a deep breath. "I like him."

Alec snapped the whip at her again, this time against the backs of her legs. Except this time, he didn't stop. Staring hungrily at the rapidly growing welts on her legs, he slapped the whip again and again, laughing loudly as blood escaped from the raw, open wound, falling in droplets onto the floor.

Clary was tossing her head back and forth, screaming and crying for _somebody, anybody _to help her.

Alec finally stopped, his chest heaving.

The only sounds were his breathing and her whimpers.

"Did that hurt, Clary?" He asked, walking around to face her.

She gave a small cry, like an injured animal, and nodded.

Alec smiled. "Would you like me to stop whipping you, you little bitch?"

She nodded again.

"Your wish is my command." He tossed the trustworthy whip aside, and grabbed the taser gun.

Clary looked at it, her eyes widening. "Alec-" He pulled the trigger, cutting her off.

Her whole entire body spasmed, and she shrieked, sounding remarkably similar to a banshee Alec had once seen in the Bone City, her eyes wide open and blank. Like she was in so much pain she'd lost herself in her own mind.

He tased her again.

Again.

And again.

By the time he'd finished, her body was limply hanging, her head drooped to the side, her mouth parted in a silent scream with blood trickling out of the corner, and her green eyes blank.

Alec felt pride wash over him, pleased with his work.

But he wasn't quite done yet.

Grabbing the knife from where it was laying on the floor by his feet, feeling neglected, he moved closer to Clary, the tip of the knife teasing the corner of her eye.

Pressing down, he forgot to grimace as he dug the knife into her eyesocket, blood squirting out as he pulled, her eye popping out. Literally. It fell out of her socket, blood escaping elong with it, only hanging by a little pink thread.

Alec pulled away. No, it wasn't enough. She was still alive.

Sighing, he thrust the knife up into her ribs.

He stepped back, and grinned. Perfect. The burning in his body vanished, the Oath fading.

His sister stepped out of the shadows, from where she'd been watching the whole time. "Took you long enough," she smirked at him, strutting over to where he stood. "I thought I was going to have to step in and take care of her myself."

He chuckled and looked over at his sister, who was smiling slyly. "You aren't going to tell Jace?"

Isabelle rolled her eyes. "Please," she scoffed. "With that little brat gone, hopefully he'll go back to normal. Enough with all this lovey-dovey shit he had going on."

She glanced over at Clary. "Lets get outta here. The mundie's beginning to reek."

Alec nodded, and began walking up the stairs, Izzy following him.

The witchlight faded as he carried it further up the stairs, and nothing but darkness and silence covered the evidence of what had just occured.

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><p><strong>Think I'm messed up in the head yet? ;)<strong>

**Review if this made you cringe. Or you know...Review...**


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